At a Glance
Material Family
Acids & Salts
Record Type
Acid
Primary Role
Synthesis Intermediate · Corrosion Inhibition
Functional Roles
Industries Served
Applications & Use Cases
- ▸ Serves as the principal raw material for manufacturing phosphonate scale and corrosion inhibitors such as HEDP, ATMP, and DTPMP used in industrial cooling water and boiler treatment.
- ▸ Acts as a key intermediate in producing phosphite (phosphonate) salts and fosetyl-type fungicides and foliar biostimulants for agricultural crop protection.
- ▸ Functions as a strong reducing agent in chemical synthesis, including the preparation of phosphite esters and organophosphorus compounds.
- ▸ Used to produce basic lead and other metal phosphites that act as heat and UV stabilizers in PVC and other polymer compounds.
- ▸ Employed as a corrosion inhibitor and additive feedstock in metal surface treatment and industrial cleaning formulations.
Physical Properties
Appearance
White to pale-yellow deliquescent crystalline solid
Molecular Weight
81.99 g/mol
Melting Point
73 C
Decomposition Temperature
approx. 200 C
Density
1.65 g/cm3
Water Solubility
Very soluble (miscible / >300 g/100 mL)
pKa1
1.3
pKa2
6.7
Acidity
Diprotic acid
Safety & Handling
Full SDS available on request
A grade-specific Safety Data Sheet (SDS) — with the complete hazard classification, handling precautions, and transport information — is supplied with every shipment and available on request. Confirm all safety and regulatory details against the SDS for your specific grade.
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DOT / UN Transport Classification
UN / DOT NumberUN 3260
Hazard Class / DivisionClass 8
Proper Shipping NameCorrosive solid, acidic, inorganic, n.o.s
Transport classification per the UN Model Regulations / 49 CFR 172.101 Hazardous Materials Table. Confirm against the grade-specific SDS (Section 14) before shipping.
Chemical Identity
CAS Number
13598-36-2
Molecular Formula
H3O3P
Molecular Weight
81.996 g/mol
IUPAC Name
phosphonic acid
PubChem CID
InChI Key
ABLZXFCXXLZCGV-UHFFFAOYSA-N
Synonyms & Trade Names
Full Description
Regulatory & registration requirements
- TSCA (US):
- REACH (EU):
- EC number: 237-066-7
Source: EPA TSCA Inventory (July 2025 release) · ECHA CHEM — retrieved 2026-07-12
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Disclaimer. Information on this page — including properties, identifiers, hazard, transport (DOT/UN) and tariff (HS) classifications, and applications — is provided for general reference and is compiled from authoritative public sources (e.g. PubChem/ECHA, 49 CFR 172.101, the Harmonized Tariff Schedule). Values are typical and are not a guaranteed specification; the Certificate of Analysis (CoA) for the lot purchased governs. Products are sold for industrial and professional use only. Nothing here is a medical, health, or efficacy claim or advice. Always consult the current Safety Data Sheet (SDS) before handling, storage, transport or disposal, and confirm regulatory status, classification and suitability for your application and jurisdiction. Hazard, transport and tariff classifications must be verified for your specific shipment. RawSource makes no warranty, express or implied, and assumes no liability for use of this information. Trademarks. Third-party trademarks and brand names are the property of their respective owners; any reference is nominative — used only to identify a comparable product — and does not imply affiliation with, sponsorship by, or endorsement by the trademark owner.